Typically, labeling machines comprise a rotating carousel, the input of which is connected to a device for feeding the containers to be labeled and the output of which is connected to a device for unloading the labeled containers.
The feeding devices are usually constituted by a feeding star conveyor, which is associated with a flat supporting element for the containers, and by belts or screw feeders for supplying the containers to the feeding star conveyor.
Similarly, the unloading devices comprise an unloading star conveyor, which is also associated with a flat element, and is intended to send the labeled containers coming from the labeling machine to an unloading belt or to further star conveyors for moving the containers.
In some cases the containers to be labeled, if they originate for example directly from a blow-molding machine, are conveyed to the labeling machine by way of one or more fixed-height star conveyors, which are provided with clamps which are adapted to support the containers at the neck.
Alternatively, the star conveyors can be constituted by disk-like elements which define, at their peripheral regions, receptacles that can be engaged by a respective portion of the neck of the container so that the “lip” can be supported on the edge of the receptacles; extending around the peripheral region of the disk is an outer ring which is intended to support the remaining part of the neck of the container.
Similarly, the unloading of the labeled containers can also involve the use of one or more fixed-height star conveyors which are structured in a similar manner to those used for feeding the containers to be labeled.
To make the application of the labels reliable, it is necessary to immobilize the containers between a supporting pan and a respective upper centering head when the containers to be labeled are in the rotating carousel.
In order to make it possible to label containers that have different heights, solutions have been proposed which involve maintaining the star conveyors for feeding and/or unloading at a fixed height, and varying the height of the supporting pans.
Solutions of this type are for example disclosed in EPA 02011658.8 and in EP 1919778.
Such implementation solutions, although conceptually valid, suffer a number of drawbacks.
In particular, in one solution it is necessary to intervene either in the structure of the labeling machine to allow the vertical movement, usually not envisaged, of the pans, or in the base supporting the pans, while in the other solution, one has to intervene manually by inserting spacers, in order to adapt the height of the supporting pans to the height of the container to be labeled.
Another disadvantage of the conventional solutions is due to the fact that the labeling assembly or assemblies associated with the rotating carousel operate at a height which on average is higher than the solutions that have the supporting pans at a fixed height, and this entails a certain inconvenience in operations to control and intervene on the labeling assemblies.
The aim of the present disclosure is to solve the above mentioned problems and overcome the drawbacks, by providing a labeling machine that is considerably easier and more practical to use than the conventional labeling machines used today.
Within this aim, the disclosure provides a labeling machine that is extremely reliable and which can be used with carousels of conventional structure.